The invention of gunpowder and its use in propelling missiles from tubes was the signal for the abolition of armour, as we have indicated, though the struggle for supremacy between the two lasted for considerably more than a century. The Eastern nations are generally credited with the discovery of the properties of a mixture of saltpetre, carbon, and sulphur so far as their use in fireworks is concerned, but it was undoubtedly to the Western nations that the knowledge and application of the propelling nature of the mixture were due. The first authentic account of its use for military purposes must be ascribed to the seventh century, when, under the name of Greek fire, it was used at the defence of Constantinople by the Byzantine emperors against the invading Saracens. The true Greek fire, however, is supposed to have contained more ingredients than the three which constitute gunpowder proper, viz. resin and naphtha, the latter being in excess, and this mixture appears to have been so inflammable and so difficult to extinguish that the terror excited by its use was out of all proportion to the destruction that it wrought. It was propelled from balistæ, projected from tubes, and carried by means of arrows which bore tow steeped in the composition, while its use in a besieged town to pour down upon assailants was probably the most efficacious. Its composition was for a long time kept secret, but the knowledge gradually spread, and during the later mediæval period its use was not unknown in England (Fig. 337). Gunpowder proper was used for the first time in the Spanish wars with the Moors in the twelfth century by both combatants; and the secret of its composition was discovered by Roger Bacon in the thirteenth century, probably from the translation of manuscripts. Schwartz, a German Frank, perfected it about a century later, and its first use in England occurred in the wars against the Scots by Edward III. in 1327, when the cannon were denominated “crakeys,” a diminutive from “crake,” the first name of the composition, which may be a corruption of “grec.” At the siege of Cambrai in 1339 cannon were in use, and they are specifically mentioned by Froissart. After that time their use became general, and in 1346 many were in operation at the battle of Creçy, the gunpowder being imported from abroad until the reign of Elizabeth, when English powder-mills were established in the country. The word artillery had been in use to denote projectile-throwing weapons anterior to the use of gunpowder, and became eventually the term by which the larger kind of firearms was designated. The construction of the first cannon was, as might be inferred, of the rudest possible description. Pieces or bars of iron were arranged longitudinally so as to form a rough tube, around which iron hoops were placed to hold them together. The powder and ball were in a separate case, open at one end to allow of the exit